The rotational motion of a metallic blade within a continuum of fluid (e.g., air) provides a heat transfer effect, but a straightforward construction is not sufficient to guarantee an efficient heat transfer apparatus. The blade geometry of the fan requires an appropriate structure to impart maximum heat to the ambient. A simple design where a conventional fan blade is replaced by a metallic material (with a heat conduction path) is limited in reducing the thermal resistance. A film heat transfer coefficient (h) of the order of 50 Watts/m2K for a conventional fan blade must be increased by a factor of five (5) in order to achieve an attractive design for future electronic cooling applications.
FIGS. 1 and 19 show a prior cooling system. FIG. 1 shows a cooling system 100 comprising a metallic fan blade 104 attached to a rotating metallic shaft 105 which rotates within a thin fluid film 108. A heat source (e.g. a chip) 106 is soldered to a substrate 110 by solder balls 112 and connected to the casing 102 by thermal paste 114. The concept of using a heat dissipating surface to rotate in a stationary fluid is considered to provide enhancements to heat transfer mechanisms. The system is referred to as a Kinetic Heat Sink (KHS).
Referring to FIG. 19, an implementation of the cooling system 100 is shown. The metallic blade 104 is shown to have a spiral pattern. However, the heat generated by the chip 106 is not efficiently conducted away. Therefore, there is a need for a cooling system that overcomes the foregoing drawbacks.